COMMUNITY FORUM

Cotton Insulation + Barrier

My cousin just used some denim cotton insulation, Ultra Touch, for his new addition and told me that it worked really well and did not itch. He said that he put a vapor barrier across the entire wall and that it gives better protection (some kind of mono fit?) Is this true?

I do not know if you are asking if the vapor barrier provides better protection or the denim insulation, or both together.

The plastic vapor barrier should be used in all insulation projects. It is even more necessary when using organic materials like cellulose or cotton because they are more prone to feed mold and mildew and rot out if water vapor condenses inside them. (Mold does not feed on fiberglass). The purpose of the plastic sheet is to keep the moisture/humidity in the warm, inside air away from the insulation. Even though the temperature can pass through it, the vapor cannot.

Fiberglass is the standard for insulation because it is the most cost efficient. It also does not collapse and lose its insulating properties over time as much or as quickly as cellulose or cotton can. Denim will cost more and probably do a fine job, though.